Melamine-formaldehyde resins are extensively used for impregnating print and overlay sheets in the manufacture of decorative laminated plastics because of their transparency, toughness, light stability, and relatively low cost. Despite the widespread use of melamine-formaldehyde resins in decorative high-pressure laminates, these resins have one major deficiency in that they are quite brittle in an unmodified state which limits their use in the preparation of decorative high-pressure postforming-type laminates. A postformable laminate is a fully-cured laminate which can nevertheless be heated and bent into a new shape. See U.S. Pat. Nos. 3,378,433 and 3,730,828. Melamine-formaldehyde resins are made postformable by the addition of a number of plasticizing agents that are widely known in the art such as glycols, polyesters, and a number of amino compounds such as guanamines, sulfonamides, etc. See U.S. Pat. Nos. 3,470,134, 2,817,614, and 3,082,180.
Although these additives enable laminates to be postformed, high temperatures (325.degree. F.) are often required. Lower temperatures are desired because many pigments are only guaranteed against discoloration up to 320.degree. F. High temperatures also increase the risk of blistering and decrease productivity since more time is required to heat the laminate. Also, prior art postformable laminates were only guaranteed to postform over a 3/4 inch radius, although occasionally a radius of 3/8 inch could be obtained under optimum conditions. The minimum postforming radius limits the range of designs which can be used.